import subprocess

def get_total_disk():
    child = subprocess.Popen(["lsblk", "-b"], stdout=subprocess.PIPE)
    out = child.stdout.readlines()
    total_disk=0
    for item in out:
        line = item.strip().split()
        if(line[5] == 'disk'):
            k = int(line[3])
            total_disk += k
    total_disk = total_disk / 1024 /1024
    return total_disk     

